The present invention relates to reinforced tape laminates and especially to glass fiber reinforced gummed tape laminates.
The use of fibers, particularly glass fibers, to reinforce gummed tapes has long been accepted as a method for substantially increasing the tear strength of the tape. Such tape laminates are typically formed by applying an adhesive to the base sheet, laying on the fiber, then applying a top sheet and pressing the laminate through a pair of squeeze rolls. The tape is generally completed by applying an adhesive to one of the outer surfaces to form a gummed or prepasted coating although, in some instances, one of the sheets may be precoated prior to formation of the laminate.
The requirements for the adhesive used in forming the laminate are stringent and include excellent paper adhesion as well as good specific adhesion to the fibers in order to give an overall strong construction. While the latter are the principal requirements, the adhesive must also possess heat and oxidation resistance, low temperature flexibility and must not bleed through the paper substrates. Originally, the adhesive used in producing the laminate were aqueous vinyl acetate based adhesive. More recently, however, tape manufacturers have switched to hot melt adhesives, most commonly those based on atactic polypropylene.